Sparking plug for internal-combustion engines



lIIIIIARTIIIEZ. SPARKING PLUG FOR INTERNAL COMBUSTION ENGINES.

APPLICATION FILED MAILZS, 1921.

Patented May 30, 1922.

IIIIIII JosE MARTINEZ, or rams, FRANCE.

sPAEKING PLUG Eon INTEENAL-coMEUsTioN ENGINES. y

Spcceation of Letters Patent. Patented Iggy 30, 1922,

Application led March 23, 1921. Serial No. 454,841.

To all whom 'it may concern:

.Be it known that I, Jos MARTINEZ, a subject of the King of Spain, and a resident ot 22 Rue du Pont Neuf, Faris, France, have invented new and useful Improvements in a Sparking Plug for Internal Combustion ltngines, (for which I have filed applications in France Jan. 14, 191.9; 1n Great Britain Dee. 20, 1919; in GermanyJune 22, 1920; in Italy .lune 22, `1920; in Belgium J une 2S, 1920; in Switzerland June 23, 1920; in Spain June 22, 1920, and in Cuba Aug. 31, 1.920), of which the following is a specification. y

The present invention relates to a sparking plug 'for internal combustion engines, in which the sheath or fitting, of insulating material, threaded upon the central electrode, is surrounded by a metal ring, litted within the body of the plug and carrying the pressure exerted by the tightening nut which is screwed in the body of the sparking plug; this arrangement has f or its object to avoid the damage of' the insulating .itting of the electrode as is the case when the tightening nut directly acts upon said insulating fitting. i

The said ring, upon which bears the tightening pressureot the' nut, is provided, at its lower part, with a bore of larger diameter, which surrounds and allows of centering a part, of larger diameter, of the insulating fitting of the electrode, which is held in place between a shoulder of the body of the plug and a shoulder ot said loose ring. The ring is located, on the greatest part oit its length, at some distance from the insulating iitting of the electrode, so as to allow of the `lree expansion thereof; this ring is provided with vents or holes, which, together with corresponding holes provided in the metal body of the plug, allow of a circulation of cooling air in the interior of the plug, around the insulating fitting et the electrode.

The electrode is surrounded, at its exterior end, with a tubular insulating part, which is seated on the loose ring and held by a nut screwed on the said end of the electrode.

This arrangement moreover enables the central electrode to be dismounted very easily and to be readily replaced, when worn out, without having to unscrew the body of the plug.

The ring, surrounding the insulating sheath of the central electrode, assures always for thiselectrode a perfect centering without any possible deformation once it has been put in place.

In the annexed drawings: Fig. 1 shows the improved sparkingplug in elevation.

Fig. 2 is a vertical axial section thereof. Fig. 3 is a vertical axial section, separately, of the metal ring adapted to center and to hold in place the central electrode.

The sparking plug comprises a metal body, provided with a screwthreaded socket a at .its lower part, a cylindrical middle part al and a polygonal head a2 at its upper part, for the screwing of the plug; the cylindrical part al of the body is pierced with vent holes a3. This metal body is provided with a cylindrical bore a4, above which is provided another cylindrical bore a6, of larger diameter than the first; a shoulder a5 is thus formed at the'lower part of the bore a6. The said bore a6 is provided with an internal screw-thread at a7. i

Within the body of the plug'is itteda metal cylindricalring, comprising alower cylindrical part of large diameter, b, surmounted by a cylindrical part b1 o1 less yless diameter; the latter is provided at its 'upper part with a liange 792. Thering thus comprises a cylindrical bore b3 and another concentric bore b4, of `larger' diameter (Fig. 3). i

The ring Z9 791 is surmounted by a tubular fitting o, of insulating material, upon which bears, with interposition of a cap el, a nut e, screwed upon the screwthreaded rod j of the central electrode (l.

The latter comprises the axial rod f having at its lower end a head f1, on which is threaded vfirst a star g, of inoxydizable metal, and then a sheath 71 -formed with mica washers, tightened by a nut i, with interposition of a washer il. This sheath comprises at a certain height mica washers of larger diameter, zl, which are fitted within the bore 54, of larger diameter, ot the ring Z) b1 ;.the whole constitutes the central part of the plug.

The said whole, located within the body a al of the plug, is maintained in position by a nut 7c, screwed into the internal screwthread a7 of the body; this nut 7c bears by an interior shoulder 701 on the flange b2 of the ring b b1, in such a manner as to press the mica washer h1 between, on the one hand, the shoulder a5 of the body a, with interposition of: av metallo-plastic joint h2, and, on the otherl hand, the shoulder of the ring b 1, with interposition of the metallo-plastic joint 7a3.

The part Y) ott the ring centers the whole central part o tthe plug within the bore ab' of the body a, of the plug7 without it being possible to produce any deformation, at the same time as the nut /c maintains the said central part in position.

Air passes through the vvent holes a oit the body and the vent holes 65 of the ring, to Cool the interior of the plug by circulating in the chamber m, provided between the insulating litting Yr of the electrode and the bore b of the ring.

In order to withdraw from the body the whole central part oi` the plug, e., the central. electrodo with its insulating litting7 it is sullicient to unserew the retaining nut la; then, by unscrewing the nut e and raising the cap el, the tubular fitting o and the ring Y; b1, the central electrode may be separated.

That I claim is:

l. A spark plug, comprising a hollow metal body having an internal Shoulder in its lower portion7 a packing ring resting on said shoulder, a central electrode, an insulating fitting surrounding said electrode and having an enlarged portion bearing on said packing ring, a second packing ring upon the upper face of said enlarged portion7 a metallic ring having an upper portion loosely surrounding the upper portion of said fitting and bearing at its lower end upon said second packing rin g, Said Inetallie ring having a lower portion of increased diameter closely fitted within the metal body and closely surrounding the enlarged portion of said Vfitting and bearing at its lower end upon said irst-Inentioned packing ring, and a nut screwed into the upper end ol the nietal body and bearing upon the nietal ring whereby to clanip the enlarged portion of the insulating fitting between the lower end ot the upper portion of the Inetal ring and the internal shoulder of the inet-alv body.

2. A spark plug, comprising a hollow metal body having an :internal shoulder in its lower portion, a packing ring resting on said shoulder, a central electrode7 an insulating litting surrounding said electrode and having` an enlarged portion bearin said packing ring, a second paeking g upon the upper face ofi said enlarged portion, a metallic ring having an upper portion loosely surrounding the upper portion of said fitting and bearing at its lower end upon said second packing ring` said metallic ring having a lower portion ot increased diameter closely fitted within the lnetal body and closely surrounding the enlarged portion olf' said fitting and bearing at its lower end upon said lirst-Inentioned packing ring, a nut screwed into the upper end olf 'the metal body and bearing upon said nietal ring7 a tubular insulating fitting bearing upon said metal ring, a cap bearing upon said fitting, and a nut Screwed upon the upper end o'l the central electrode and bearing upon said cap.

In testimony whereof I have signed iny naine to this specification.

Jose MA1-riunita.

IVitneSses P. ARMIQGAND, M. DnromMoNT. 

